How To Remove The Cabinet, Bottom Board And Front Panel; Before Starting The Repairing; How To Remove The Power Ic - Technics SU-8022 Service Manual

"022/K SU-S022/K
· . . . 12
· . . . 13
· . . . 14
· ... 14
.15~16
· . . . 17
· . . . 17
· ... 17
· ... 18
2
~
1)
Jtlets
Left ch.
power amplifier I
• NOTE
main Ctmplifier ci
Right ch.
power amplifier le
Equalizer
amplifier circuitry
The unit is provided with the speaker circuit protection fuses at the right and left channels respectively. The fuse is to
prevent the power IC from destruction, should the speaker terminals be short-circuited. Accordingly, if the unit fails to
function upon completion of the speaker connections, check the speaker circuit protection fuses first of all for possible
blowing.
• HOW TO REMOVE THE CABINET, BOTTOM BOARD AND FRONT PANEL
How to remove the cabinet
1. Remove the 4 setscrews
(CD ~
@
in Fig. 1) on the side and 4 setscrews (@~ ®
in Fig. 2) on the back of the cabinet.
2. Shift the cabinet backward and lift it upward. (Arrow
G
in Fig. 1)
Fig. 1
How to detach the bottom board
1. Remove the 4 setscrews
(@
~
@
in Fig. 3) used to
secure bottom board and 4 setscrews (
®
~
@ in
Fig. 3) for the legs. Then the bottom board can be
detached.
Fig. 2
How 10 detach the front panel
1. Remove the 4 setscrews (
@ -
®
in Fig. 4) and then
carefully pull the front panel toward you.
~
y-®
T
~
~
(9)@
r®
,9
T
~set
Foot
@
~
Bottom Board
Fig. 3
• BEFORE STARTING THE REPAIRING
Before adjusting or repairing, be sure to short-circuit
opposite poles of the 8200pF capacitors (C501, 502) with a
resistor approximately of "50[2, 5W" for discharging the
charged voltage .
Short-circuiting with a screw driver and the like is not only
dangerous, but may destroy transistors and diodes, and
should therefore be avoided.
• HOW TO REMOVE THE POWER IC
1. Remove the solder of power IC for both Lch
and Rch.
2. Remove the 3 setscrews
(CD - ®
in Fig. 5) use
to fasten the heat sink from the center bracket.
3. Remove the heat sink along with power IC in
the direction of arrow
G
(Fig. 6)
4. Remove the 2 setscrews (@, CID in Fig. 6) used
to secure the power IC on the heat sink, and
then pull the power IC in the direction of arrow
@.
5. When mounting the power IC, apply silicone
compound (or equivalent heat diffuser) to the
back of power I C, and then follow the steps 1
- 4 reversely.
POWER IC
IIC3031
CENTER BRACKET
Fig. 5
POWER IC
IIC3041
SU-8022/K
~
19
i
Fig. 4
Electrolytic Capacitor
Resistor(500,50W)
r=J
Lspeaker Tenniral
J
Speaker Circuit Rear Panel
Protection Fuses
PRINTED CIRCUIT BOARD
Fig. 6
LEFT CH
POWER le